The present invention relates to the discovery by a collection of devices of their relative locations using sound.
Voice control of apparatus is becoming more common and there are now well developed technologies for speech recognition particularly in contexts that only require small vocabularies.
However, a problem exists where there are multiple voice-controlled devices in close proximity since their vocabularies are likely to overlap giving rise to the possibility of several different devices responding to the same voice command. In fact, the problem is more general and arises wherever there are multiple devices in close proximity whose input or output overlap.
One approach to effecting selective device activation amongst a group of devices is to ascertain the position of the user relative to the devices, and thus determine to which device the user is closest. This method relies on a knowledge of the device locations.
Whilst it is, of course, possible for an installer to measure the position of each device with respect to some external reference and input the measured device positions into a device activation control system, this approach does not lend itself to a situation where the devices may be frequently moved and devices added or removed from the device group. Even equipping each device with a system such as GPS for determining its own absolute location is not satisfactory because reception and location accuracy using GPS inside a building is often unreliable and unlikely to give the necessary location resolution required between member devices a group of devices situated in the same room.
Furthermore, device location discovery will generally be provided as an auxiliary device function rather than as the main device function, and it is therefore preferable, for cost reasons, that location discovery be done using device features already required for the main device function.
Accordingly, it is an object of the present invention to provide a way of enabling devices to discover their relative locations which is easy to deploy and, preferably, can utilise device features already present for other purposes.
According to a first aspect of the present invention, there is provided a location discovery method for a plurality of devices equipped with respective electromagnetic communication subsystems, sound emitters and sound receivers; the method comprising the steps of:
a) emitting from each device both a test sound and, via its communications subsystem, a timing-reference signal;
b) receiving the test sound and timing-reference signal emitted by each device at at least two other said devices and determining respective measures of the transit times of the test sound between emitting and receiving devices, the timing-reference signal enabling the timing of emission of the test sound to be related to the timing of its receipt; and
c) using the transit-time measures to determine the relative locations of the devices. The transit-time measure can, for example, be the transit time itself or, indeed, a derivative measure such as the distance between the emitting and receiving devices.
According to a second aspect of the present invention, there is provided an auto-location method for a plurality of voice-controlled devices equipped with respective microphones and electric or electromagnetic communication means, wherein each device is caused to emit a sound at the same time as sending an electric or electromagnetic signal, the latter acting as a timing point enabling the other devices to determine their distance from the emitting device, the devices exchange their distances from other devices whereby to enable each device to calculate the relative locations of all devices.
According to a third aspect of the present invention, there is provided a device comprising:
a sound emitter for emitting a test sound;
a sound receiver for receiving a test sound;
an electromagnetic communications subsystem for sending and receiving timing-reference signals;
an emission control arrangement for sending a test sound via the sound emitter and a related timing-reference signal via the communications subsystem;
a measurement arrangement operative upon the receipt of a test sound and related timing-reference signal from another device to determine a measure of the transit time of that test sound and thereby of the distance between the two devices; and
a distribution arrangement for sending the determined measure to at least one other device via the communications subsystem.
According to a fourth aspect of the present invention, there is provided a device comprising:
a sound emitter for emitting a test sound;
a sound receiver for receiving a test sound;
an electromagnetic communications subsystem for sending and receiving timing-reference signals;
an emission control arrangement for sending a test sound via the sound emitter and a related timing-reference signal via the communications subsystem;
a measurement arrangement operative upon the receipt of a test sound and timing-reference signal from another device to determine a measure of the transit time of that test signal and thereby of the distance between the two devices; and
a location-determination arrangement for receiving, via said communications subsystem, further measures that have been determined by other devices, and using these further measures and the measure determined by its own measurement arrangement to determine the relative locations of the devices.
According to a fifth aspect of the present invention, there is provided a handheld device comprising:
a sound emitter for emitting a test sound;
an electromagnetic communications subsystem for sending and receiving signals;
an emission control arrangement for sending a test sound via the sound emitter and a related timing-reference signal via the communications subsystem; and
a location-determination arrangement for receiving, via said communications subsystem, measures of the transit time of the test sound to other devices, and data concerning the locations of those other devices relative to one another, the location-determination arrangement being operative to use the receive measures and data to determine the location of the handheld device.